Water-based resin dispersion and coating material

ABSTRACT

The present invention relates to an aqueous resin dispersion, obtained by subjecting a polymerizable compound (C) containing a compound (C1) having a carbon-carbon unsaturated bond to an emulsion polymerization in the presence of a surfactant (A) and a surfactant (B) free from a radical-polymerizable substituent.

TECHNICAL FIELD

The present invention relates to an aqueous resin dispersion, and morespecifically relates to an aqueous resin dispersion obtained bysubjecting a polymerizable compound to emulsion polymerization by usinga specific surfactant. Further, the present invention relates to acoating material containing the aqueous resin dispersion describedabove.

BACKGROUND ART

In recent years, in consideration of the global environment and the workenvironment, transition from a solvent base to an aqueous baseprogresses in various applications, including a coating material, andthe required performance of an aqueous resin dispersion, which is a rawmaterial therefor, has increased. In particular, an emulsionpolymerization method has been used as a useful method for producing theaqueous resin dispersion.

However, since the emulsion polymerization method uses a surfactant,there are problems of the occurrence of foam, the decrease in waterresistance of coating film, the elution of surfactant from the coatingfilm and the like. Therefore, in Patent Documents 1 and 2, emulsionpolymerization methods using a surfactant having a polymerizable groupare disclosed.

PRIOR ART DOCUMENT Patent Document

Patent Document 1: JP-A-63-183998

Patent Document 2: JP-A-8-41113

SUMMARY OF THE INVENTION Problems that the Invention is to Solve

However, the methods described in Patent Documents 1 and 2 can suppressthe occurrence of foam, the decrease in water resistance of coating filmand the elution of surfactant from the coating film, but there is aproblem in that wettability to a base material is poor. Further, inorder to improve the wettability to a base material, when the surfactanthaving a polymerizable group described in Patent Documents 1 and 2 and asurfactant having no polymerizable group are used in combination, theoccurrence of foam, the decrease in water resistance of coating film,the elution of surfactant from the coating film, and the like takeplace, and it has been found that the advantage of the surfactant havinga polymerizable group is lost.

Therefore, the present invention provides an aqueous resin dispersionwhich, not only suppresses the occurrence of foam, the decrease in waterresistance of coating film and the elution of surfactant from thecoating film, but also is excellent in the wettability to a basematerial.

Means for Solving the Problems

In order to solve the problems described above, the aqueous resindispersion according to the present invention is obtained by subjectinga polymerizable compound (C) containing a compound (C1) having acarbon-carbon unsaturated bond to an emulsion polymerization in thepresence of a surfactant (A) represented by a general formula (I) shownbelow and a surfactant (B) free from a radical-polymerizablesubstituent.

In the general formula (I), R⁰ represents an alkyl group having a carbonnumber of from 1 to 4, R¹ represents at least one group selected fromsubstituents represented by structural formulae described above, inthese structural formulae, R² represents a hydrogen atom or a methylgroup, D represents a substituent represented by general formula D-1 orD-2 shown above, in these structural formulae, R³ represents a hydrogenatom or a methyl group, m1 represents a number of from 1 to 2, m2represents a number of from 1 to 3, m3 represents a number of 0 or 1, AOrepresents an oxyalkylene group having a carbon number of from 2 to 4, nis an average addition molar number of alkylene oxide and represents anumber in a range of from 0 to 1,000, and X represents a group selectedfrom —(CH₂)_(a)—SO₃M, —(CH₂)_(b)—COOM, —PO₃M₂, —P(Z)O₂M, and—CO—CH₂—CH(SO₃M)-COOM, in these structural formulae, a and b eachrepresents a number of from 0 to 4, Z represents a residue in which X iseliminated from the general formula (I), and M each represents ahydrogen atom, an alkali metal atom, an alkaline earth metal atom, analkyl ammonium, an alkanol ammonium, or an ammonium.

According to the constitution described above, the aqueous resindispersion which, not only suppresses the occurrence of foam, thedecrease in water resistance of coating film and the elution ofsurfactant from the coating film, but also is excellent in thewettability to a base material, is achieved.

In the aqueous resin dispersion having the constitution described above,a ratio of the surfactant (B) is preferably from 5 to 80 parts by massbased on 100 parts by mass of the surfactant (A).

According to the constitution described above, the aqueous resindispersion which, not only further suppresses the occurrence of foam,the decrease in water resistance of coating film and the elution ofsurfactant from the coating film, but also is more excellent in thewettability to a base material, is achieved.

The coating material according to the present invention is onecontaining the aqueous resin dispersion described above.

Advantage of the Invention

According to the present invention, an aqueous resin dispersion which,not only suppresses the occurrence of foam, the decrease in waterresistance of coating film and the elution of surfactant from thecoating film, but also is excellent in the wettability to a basematerial, is obtained.

MODE FOR CARRYING OUT THE INVENTION

Preferred embodiments of the present invention will be describedhereinafter. In the present invention, “(meth)acryl” means “acryl” or“methacryl”, “(meth)acrylate” means “acrylate” or “methacrylate”, and“(meth)allyl” means “allyl” or “methallyl”.

The aqueous resin dispersion of the present embodiment is one obtainedby subjecting a polymerizable compound (C) containing a compound (C1)having a carbon-carbon unsaturated bond to an emulsion polymerization inthe presence of a surfactant (A) represented by general formula (I)shown below and a surfactant (B) free from a radical-polymerizablesubstituent.

The surfactant (A) in the present invention is one represented by thegeneral formula (I) described above. In the general formula (I), R⁰represents an alkyl group having a carbon number of from 1 to 4, R¹represents at least one group selected from the substituents representedby structural formulae described above, in the structural formulae, R²represents a hydrogen atom or a methyl group, D represents thesubstituent represented by general formula D-1 or D-2 described above,in the structural formulae, R³ represents a hydrogen atom or a methylgroup, m1 represents a number of from 1 to 2, m2 represents a number offrom 1 to 3, and m3 represents a number of 0 or 1. Here, m1, m2 and m3satisfy 2≦(m1+m2+m3)≦5.

Further, AO represents an oxyalkylene group having a carbon number offrom 2 to 4, n is an average addition molar number of alkylene oxide andrepresents a number in a range of from 0 to 1,000.

X represents a group selected from —(CH₂)_(a)—SO₃M, —(CH₂)_(b)—COOM,—PO₃M₂, —P(Z)O₂M, and —CO—CH₂—CH(SO₃M)-COOM, in the structural formulae,a and b each represents a number of from 0 to 4, Z represents a residuein which X is eliminated from the general formula (I), and M eachrepresents a hydrogen atom, an alkali metal atom, an alkaline earthmetal atom, an alkyl ammonium, an alkanol ammonium, or an ammonium.

The substituent R⁰ in the general formula (I) described above representsan alkyl group having a carbon number of from 1 to 4. The substituent R⁰is preferably an alkyl group having a carbon number of from 1 to 2. Thesubstituent R¹ in the general formula (I) described above represents atleast one group selected from the substituents represented by thestructural formulae described above. The substituent R¹ described aboveis preferably the substituent represented by the structural formuladescribed in the center of the structural formulae described above. m2is an average substitution number of the substituent R¹ and m2 is anumber of from 1 to 3. m2 is preferably from 1.05 to 1.8.

The substituent D in the general formula (I) described above is onerepresented by D-1 or D-2. Specifically, the substituent represented byD-1 is a 1-propenyl group or a 2-methyl-1-propenyl group, and thesubstituent represented by D-2 is a (meth)allyl group. The substituent Dis preferably substituted into an ortho position (2-position or6-position) of the general formula (I). m1 is an average substitutionnumber of the substituent D and m1 is a number of from 1 to 2. From thestandpoint that not only the occurrence of foam, the decrease in waterresistance of coating film and the elution of surfactant from thecoating film are suppressed, but also the wettability to a base materialis more excellent, m1 is preferably from 1 to 1.5. Moreover, from thestandpoint that not only the occurrence of foam, the decrease in waterresistance of coating film and the elution of surfactant from thecoating film are suppressed, but also the wettability to a base materialis more excellent, it is preferred that the substituent D includes D-1,and it is more preferred that D-1 is included alone or a ratio of D-1 toD-2 (D-1)/(D-2) is 2 or more.

AO in the general formula (I) described above is an oxyalkylene grouphaving a carbon number of from 2 to 4, and includes, for example, anoxyalkylene group having a carbon number of 2, for example, anoxyethylene group, an oxyalkylene group having a carbon number of 3, forexample, an oxypropylene group, an oxy-1-methylethylene group or anoxy-2-methylethylene group, and an oxyalkylene group having a carbonnumber of 4, for example, an oxybutylene group, an oxy-1-methylpropylenegroup, an oxy-2-methylpropylene group, an oxy-3-methylpropylene group,an oxy-1,2-dimethylethylene group, or an oxy-1-ethylethylene group.

As to the AO, from the standpoint that polymerization stability,chemical stability and mechanical stability are more excellent, it ispreferred to contain an oxyalkylene group having a carbon number of 2,and it is more preferred to contain an oxyethylene group. From thesimilar standpoint, the content of the oxyalkylene group having a carbonnumber of 2 is preferably from 50 to 100% by mole, more preferably from70 to 100% by mole, in the AO.

n in the general formula (I) described above is an average additionmolar number of alkylene oxide and is a number of from 0 to 1,000. Inthis range, from the standpoint that polymerization stability, chemicalstability and mechanical stability are more excellent, it is preferablya number larger than 0, more preferably 1 or more, and still morepreferably 3 or more. From the standpoint that polymerization stabilityis more excellent and the average particle diameter is more easilycontrolled, it is preferably 100 or less, more preferably 70 or less,and still more preferably 50 or less.

X in the general formula (I) described above is a group selected from—(CH₂)_(a)—SO₃M, —(CH₂)_(b)—COOM, —PO₃M₂, —P(Z)O₂M, and—CO—CH₂—CH(SO₃M)-COOM. In the structural formulae, a and b eachrepresents a number of from 0 to 4, and Z represents a residue in whichX is eliminated from the general formula (I) described above.

M each is a hydrogen atom, an alkali metal atom, an alkaline earth metalatom, an alkyl ammonium, an alkanol ammonium, or an ammonium. The alkalimetal atom includes, for example, lithium, sodium and potassium. Thealkaline earth metal atom includes, for example, magnesium and calcium.The alkyl ammonium includes, for example, monomethyl ammonium, dimethylammonium, trimethyl ammonium, monoethyl ammonium, diethyl ammonium,triethyl ammonium, monopropyl ammonium, dipropyl ammonium, and tripropylammonium. The alkanol ammonium includes, for example, monoethanolammonium, diethanol ammonium and triethanol ammonium.

Since the polymerization stability is more excellent, X is preferably—(CH₂)_(a)—SO₃M, —PO₃M₂ or —P(Z)O₂M, and more preferably —SO₃M, —PO₃M₂or —P(Z)O₂M.

The production method of the surfactant (A) represented by the generalformula (I) described above is not particularly limited, and variousmethods can be adopted. For example, a compound in which X in thegeneral formula (I) is a hydrogen atom is obtained by subjecting aphenol derivative having a polymerizable group in an aromatic ring toaddition polymerization with alkylene oxide. Subsequently, X issubstituted with at least one group selected from —(CH₂)_(a)—SO₃M,—(CH₂)_(b)—COOM, —PO₃M₂, —P(Z)O₂M, and —CO—CH₂—CH(SO₃M)-COOM accordingto known methods, thereby obtaining the surfactant (A) represented bythe general formula (I).

The method of producing, among the phenol derivatives having apolymerizable group in an aromatic ring, a phenol derivative having apolymerizable group in an aromatic ring, in which the substituent D isD-2, includes, for example, (s1-1) a method of subjecting a phenolderivative having a substituent in an aromatic ring and an allyl halideto a reaction, and (s1-2) a method of subjecting a phenol and an allylhalide to a reaction, and then introducing a substituent into thearomatic ring.

Hereinafter, as to the method of (s1-1), a case where a styrenatedphenol is used as the phenol derivative having a substituent in anaromatic ring is described as an example. Hereinafter, a styrenated(alkyl) phenol means a styrenated phenol or a styrenated alkylphenol.

In the general formula (I) described above, as to the polymerizableunsaturated group represented by the substituent D, as described above,D-1 is a 1-propenyl group or a 2-methyl-1-propenyl group, and D-2 is anallyl group or a methallyl group. Among them, the (meth)allyl group asD-2 can be introduced by a (meth)allylation reaction of a styrenated(alkyl) phenol. Specifically, for example, a (meth)allyl halide and astyrenated (alkyl) phenol are allowed to react in the presence of abasic substance, for example, sodium hydroxide or potassium hydroxide,and then further subjected to a reaction at 80 to 120° C., therebyobtaining a (meth)allyl styrenated (alkyl) phenol. Here, by adjustingthe use amounts of the (meth)allyl halide or basic substance to thestyrenated (alkyl) phenol or the reaction temperature, m1 in the generalformula (I) can be set to the desired number.

Reaction formulae (i) to (iv) shown below are reaction formulae in thecase where styrenated phenol is used as the styrenated (alkyl) phenol,allyl chloride is used as the (meth)allyl halide, and sodium hydroxideis used as the basic substance, as an example. In the reaction formulae(i) and (ii), a compound in which one allyl group is introduced isobtained, and in the reaction formulae (iii) and (iv), a compound inwhich two allyl groups are introduced is obtained.

The method of producing, among the phenol derivatives having apolymerizable group in an aromatic ring, a phenol derivative having apolymerizable group in an aromatic ring, in which the substituent D isD-1, includes, for example, (s2-1) a method of subjecting the reactionproduct obtained by the (s1-1) to a Claisen rearrangement reaction inthe presence of an alkali catalyst, and (s2-2) a method of subjecting aphenol and an allyl halide to a reaction, then to a Claisenrearrangement reaction in the presence of an alkali catalyst, andthereafter introducing a substituent into the aromatic ring. Here, it isnot necessary that a reaction rate of the Claisen rearrangement reactionis 100% and a (meth)allyl group may be remained. Further, the Claisenrearrangement reaction may be performed simultaneously with theintroduction of an oxyalkylene group (AO)_(n) described below.

Next, a method for introducing an oxyalkylene group (AO)_(n) into aphenol derivative having a polymerizable group in an aromatic ring isdescribed. The method for introducing an oxyalkylene group (AO)_(n)includes, for example, a method of adding a predetermined amount ofalkylene oxide to a phenol derivative having a polymerizable group in anaromatic ring by a known method. According to the method, a compound inwhich X in the general formula (I) is a hydrogen atom is obtained.

Subsequently, X in the resulting compound in which X in the generalformula (I) is a hydrogen atom is substituted with at least one groupselected from —(CH₂)_(a)—SO₃M, —(CH₂)_(b)—COOM, —PO₃M₂, —P(Z)O₂M, and—CO—CH₂—CH(SO₃M)-COOM, thereby obtaining the surfactant (I) of thepresent invention. A method for the substitution reaction is notparticularly limited, and it can be performed by a known method.

The method for substituting X with —SO₃M (case in which a in—(CH₂)_(a)—SO₃M is 0) includes, for example, a method of subjecting acompound in which X in the general formula (I) is a hydrogen atom to areaction with sulfamic acid, sulfuric acid, sulfuric anhydride, fumingsulfuric acid, or chlorosulfonic acid. According to the method, thesurfactant (A) in which M is a hydrogen atom is obtained.

The method for substituting X with —(CH₂)_(a)—SO₃M (in which a is from 1to 4) includes, for example, a method of subjecting a compound in whichX in the general formula (I) is a hydrogen atom to a reaction withpropanesultone or butanesultone. According to the method, the surfactant(A) in which M is a hydrogen atom is obtained.

The method for substituting X with —(CH₂)_(b)—COOM includes, forexample, a method of oxidizing a compound in which X in the generalformula (I) is a hydrogen atom or an alkali metal atom, and a method ofsubjecting a compound in which X in the general formula (I) is ahydrogen atom or an alkali metal atom to a reaction with amono-halogenated acetic acid. Further, a method of subjecting a compoundin which X in the general formula (I) is a hydrogen atom or an alkalimetal atom to a reaction with acrylonitrile or an acrylic acid ester andthen to saponification with alkali.

The method for substituting X with —PO₃M₂ or —P(Z)O₂M includes, forexample, a method of subjecting a compound in which X in the generalformula (I) is a hydrogen atom to a reaction with phosphorus pentoxide,polyphosphoric acid, orthophosphoric acid, or phosphorus oxychloride.According to the method, the surfactant (A) in which M is a hydrogenatom is obtained. Here, the case of —PO₃M₂ is a monoester compound, andthe case of —P(Z)O₂M is a diester compound, and the surfactant (A) isordinarily obtained as a mixture thereof. According to the presentinvention, the mixture may be used as it is or may be subjected to aseparation and only either one may be used. A method for increasing acontent ratio of the monoester compound includes a method in which thereaction described above is performed in the presence of water.

The method for substituting X with —CO—CH₂—CH(SO₃M)-COOM includes, forexample, a method of subjecting a compound in which X in the generalformula (I) is a hydrogen atom to a reaction with maleic anhydride toperform mono-esterification, and then further subjecting to a reactionwith anhydrous sodium sulfite. According to the method, the surfactant(A) in which M is a hydrogen atom is obtained.

The production method of the surfactant (A) in which M is an alkalimetal atom, an alkaline earth metal atom, an alkyl ammonium, an alkanolammonium, or an ammonium includes, for example, a method of subjectingthe surfactant (A) in which M is a hydrogen atom obtained according tothe production method described above to a reaction with an alkali metalhydroxide, an alkaline earth metal hydroxide, an alkyl amine, analkanolamine, or ammonia.

As the surfactant (B) free from a radical-polymerizable substituent inthe present invention, a nonionic surfactant, an anionic surfactant or acationic surfactant can be used.

The nonionic surfactant includes, for example, a polyoxyalkylene alkylphenyl ether, a polyoxyalkylene alkyl ether, a polyoxyalkylenestyrenated phenyl ether, a polyoxyalkylene benzylated phenyl ether, apolyoxyalkylene cumyl phenyl ether, a fatty acid polyethylene glycolether, a polyoxyalkylene sorbitan fatty acid ester, and a sorbitan fattyacid ester.

The anionic surfactant includes, for example, a fatty acid soap, a rosinacid soap, an alkyl sulfonic acid salt, an alkylaryl sulfonic acid salt,an alkyl sulfuric acid ester salt, and an alkyl sulfosuccinic acid salt.Further, a sulfuric acid ester salt, a phosphoric acid ester salt, anether carboxylic acid salt, a sulfosuccinic acid salt, or the like ofthe nonionic surfactants described above are also exemplified. The saltincludes, for example, an alkali metal salt, for example, lithium,sodium or potassium, an alkaline earth metal salt, for example,magnesium or calcium, an alkyl ammonium salt, for example, monomethylammonium, dimethyl ammonium, trimethyl ammonium, monoethyl ammonium,diethyl ammonium, triethyl ammonium, monopropyl ammonium, dipropylammonium, or tripropyl ammonium, an alkanol ammonium salt, for example,monoethanol ammonium, diethanol ammonium or triethanol ammonium, and anammonium salt.

The cationic surfactant includes, for example, astearyltrimethylammonium salt, a cetyltrimethylammonium salt, alauryltrimethylammonium salt, a dialkyldimethylammonium salt, analkyldimethylbenzylammonium salt, and analkyldimethylhydroxyethylammonium salt. The salt includes, for example,an alkylsulfate salt, for example, ethyl sulfate, and a chloride.

Among them, since the chemical stability is more excellent, a nonionicsurfactant is preferred, and a polyoxyalkylene alkyl phenyl ether, apolyoxyalkylene alkyl ether and a polyoxyalkylene styrenated phenylether are more preferred.

The polymerizable compound (C) in the present invention contains acompound (C1) having a carbon-carbon unsaturated bond. The compound (C1)having a carbon-carbon unsaturated bond includes, for example, an α-βunsaturated carboxylic acid, an α-β unsaturated carboxylic acid ester,an α-β unsaturated amide and, an unsaturated hydrocarbon.

The α-β unsaturated carboxylic acid includes, for example, (meth)acrylicacid, acrylic acid dimer, crotonic acid, itaconic acid, and maleic acid.

The α-β unsaturated carboxylic acid ester includes, for example, a(meth)acrylic acid monoalkyl ester, for example, methyl (meth)acrylate,ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate,n-butyl (meth)acrylate, isobutyl (meth)acrylate, n-hexyl (meth)acrylate,2-ethylhexyl (meth)acrylate, cyclohexyl (meth)acrylate, isooctyl(meth)acrylate, n-octyl (meth)acrylate, nonyl (meth)acrylate, isononyl(meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl(meth)acrylate, isoundecyl (meth)acrylate, dodecyl (meth)acrylate, orisododecyl (meth)acrylate; a polyol poly(meth)acrylate, for example,ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate,triethylene glycol di(meth)acrylate, polyethylene glycoldi(meth)acrylate, propylene glycol di(meth)acrylate, dipropylene glycoldi(meth)acrylate, tripropylene glycol di(meth)acrylate, polypropyleneglycol di(meth)acrylate, 1,3-butylene glycol di(meth)acrylate,1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate,1,9-nonanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate,trimethylolpropane tri(meth)acrylate, tetramethylolmethanetri(meth)acrylate, tetramethylolmethane tetra(meth)acrylate, glycerolmethacrylate acrylate, or glycerol di(meth)acrylate; a (meth)acrylicacid fluoroalkyl ester, for example, trifluoroethyl (meth)acrylate,tetrafluoropropyl (meth)acrylate or octafluoropentyl (meth)acrylate; a(meth)acrylic acid hydroxyalkyl ester, for example, 2-hydroxyethyl(meth)acrylate or 2-hydroxypropyl (meth)acrylate; an epoxygroup-containing (meth)acrylic acid ester, for example, glycidyl(meth)acrylate or allyl glycidyl ether; an alkoxysilyl group-containing(meth)acrylic acid ester, for example,γ-(meth)acryloxyethyltrimethoxysilane,γ-(meth)acryloxyethyltriethoxysilane,γ-(meth)acryloxypropyltrimethoxysilane,γ-(meth)acryloxypropyltriethoxysilane,γ-(meth)acryloxypropylmethyldimethoxysilane,γ-(meth)acryloxypropyldimethylmethoxysilane,γ-(meth)acryloxypropylmethyldiethoxysilane,γ-(meth)acryloxypropyldimethylethoxysilane,γ-(meth)acryloxypropyltrichlorosilane,γ-(meth)acryloxypropylmethyldichlorosilane,γ-(meth)acryloxypropyldimethylchlorosilane,γ-(meth)acryloxypropyltripropoxysilane,γ-(meth)acryloxypropylmethyldipropoxysilane,γ-(meth)acryloxypropyltributoxysilane,γ-(meth)acryloxybutyltrimethoxysilane,γ-(meth)acryloxypentyltrimethoxysilane,γ-(meth)acryloxyhexyltrimethoxysilane,γ-(meth)acryloxyhexyltriethoxysilane,γ-(meth)acryloxyoctyltrimethoxysilane,γ-(meth)acryloxydecyltrimethoxysilane,γ-(meth)acryloxydodecyltrimethoxysilane, orγ-(meth)acryloxyoctadecyltrimethoxysilane; an amino group-containing(meth)acrylic acid ester, for example, dimethylaminoethyl(meth)acrylate; an alkoxy group-containing (meth)acrylic acid ester, forexample, 2-methoxyethyl (meth)acrylate, butoxyethyl (meth)acrylate ormethoxytriethylene glycol (meth)acrylate; and a carbonylgroup-containing (meth)acrylic acid ester, for example,2-(acetoacetoxy)ethyl (meth)acrylate.

The α-β unsaturated amide includes, for example, acrylamide,methacrylamide, N-methylolacrylamide, and butoxy N-methylolacrylamide.

The unsaturated hydrocarbon includes, for example, styrene, α-methylstyrene, vinyl toluene, dimethyl styrene, tert-butyl styrene, anddivinylbenzene.

Compounds other than those described above, which can be used as thecompound (C1) having a carbon-carbon unsaturated bond, includes, forexample, vinyltrimethoxysilane, vinyltriethoxysilane,vinyltripropoxysilane, vinylmethyldimethoxysilane,vinylmethyldiethoxysilane, vinylmethyldipropoxysilane,tris(meth)acryloyloxy phosphate, diallyl terephthalate,tetraallyloxyethane, tri(meth)allyl isocyanurate, diacetone acrylamide,allyl acetoacetate, acrylonitrile, methacrylonitrile, sodiumstyrenesulfonate, vinyl acetate, vinyl propionate, neononanoic acidvinyl ester, neodecanoic acid vinyl ester, vinyl chloride, vinylidenechloride, alkyl vinyl ether, vinyl fluoride, vinylidene fluoride,trichloroethylene, tetrafluoroethylene, 2-chloropropene,2-fluoropropene, hexafluoropropene, butadiene, isoprene, chloroprene,ethylene, maleic anhydride, methyl maleate, and sodium vinylsulfonate.

As the compound (C1) having a carbon-carbon unsaturated bond, one kindof compound may be used alone or combination of plural compounds may beused.

The compound (C1) having a carbon-carbon unsaturated bond preferablycontains an α-β unsaturated carboxylic acid ester, and more preferablycontains a (meth)acrylic acid ester.

The total amount of the surfactant (A) and the surfactant (B) in thepresent invention is preferably 0.15 parts by mass or more, morepreferably 0.5 parts by mass or more, still more preferably 1 part bymass or more, based on 100 parts by mass of the polymerizable compound(C). Also, it is preferably 20 parts by mass or less, more preferably 15parts by mass or less, and still more preferably 10 parts by mass orless. By controlling it in the range described above, the occurrence offoam, the decrease in water resistance of coating film and the elutionof surfactant from the coating film can be further suppressed.

The use amount of the surfactant (B) in the present invention ispreferably 5 parts by mass or more, more preferably 10 parts by mass ormore, based on 100 parts by mass of the surfactant (A). Also, it ispreferably 200 parts by mass or less, more preferably 100 parts by massor less, still more preferably 80 parts by mass or less, andparticularly preferably 50 parts by mass or less. By controlling it inthe range described above, not only the occurrence of foam, the decreasein water resistance of coating film and the elution of surfactant fromthe coating film can be further suppressed, but also the wettability toa base material is more excellent.

The use amount of the surfactant (A) in the present invention ispreferably 0.1 parts by mass or more, more preferably 0.3 parts by massor more, still more preferably 0.5 parts by mass or more, based on 100parts by mass of the polymerizable compound (C). Also, it is preferably15 parts by mass or less, more preferably 10 parts by mass or less, andstill more preferably 8 parts by mass or less. By controlling it in therange described above, not only the occurrence of foam, the decrease inwater resistance of coating film and the elution of surfactant from thecoating film can be further suppressed, but also the wettability to abase material is more excellent.

The use amount of the surfactant (B) in the present invention ispreferably 0.05 parts by mass or more, more preferably 0.1 parts by massor more, still more preferably 0.3 parts by mass or more, based on 100parts by mass of the polymerizable compound (C). Also, it is preferably5 parts by mass or less, more preferably 3 parts by mass or less, andstill more preferably 2 parts by mass or less. By controlling it in therange described above, not only the occurrence of foam, the decrease inwater resistance of coating film and the elution of surfactant from thecoating film can be further suppressed, but also the wettability to abase material is more excellent.

The emulsion polymerization method for obtaining the aqueous resindispersion of the present invention is not particularly limited as longas it is a method in which the polymerizable compound (C) is subjectedto emulsion polymerization in the presence of the surfactant (A)represented by the general formula (I) and the surfactant (B) free froma radical-polymerizable substituent. As such an emulsion polymerizationmethod, for example, a method in which the polymerizable compound (C) isadded to an aqueous solution containing water, the surfactant (A)represented by the general formula (I) and the surfactant (B) free froma radical-polymerizable substituent is exemplified. As to the additionof the polymerizable compound (C), the total amount thereof may be addedat once, it may be added dividedly in plural times or it may be addeddropwise.

As another emulsion polymerization method, a method in which apre-emulsion obtained by emulsifying in advance the surfactant (A)represented by the general formula (I), the surfactant (B) free from aradical-polymerizable substituent and the polymerizable compound (C) inwater and an aqueous solution containing a polymerization initiator aremixed is exemplified. In the case of mixing the pre-emulsion with theaqueous solution containing a polymerization initiator, the total amountthereof may be mixed at once, at least one of them may be mixeddividedly in plural times or at least one of them may be added dropwise.The preparation method of the pre-emulsion is not particularly limitedand includes, for example, a method in which the surfactant (A)represented by the general formula (I) and the surfactant (B) free froma radical-polymerizable substituent are dissolved in water, and thepolymerizable compound (C) is added thereto, followed by stirring.Further, in the preparation of the pre-emulsion, an organic solventmiscible with water, for example, methanol may be used in combinationtherewith.

The reaction temperature in the emulsion polymerization method is notparticularly limited and, for example, it is preferably from 50 to 100°C., more preferably from 60 to 95° C. The reaction temperature may bemaintained constant from the start of the reaction or may be changedduring the reaction. The reaction time in the emulsion polymerizationmethod is not particularly limited, is able to be appropriatelycontrolled based on the progress of the reaction, and is usuallyapproximately from 2 to 9 hours.

In the emulsion polymerization, a protective colloid agent, a chaintransfer agent, a polymerization initiator, and a crosslinking agent canbe used.

The protective colloid agent includes, for example, completelysaponified polyvinyl alcohol (PVA), partially saponified PVA,hydroxyethyl cellulose, carboxymethyl cellulose, methyl cellulose,polyacrylic acid, and polyvinylpyrrolidone. By performing the emulsionpolymerization in the presence of the protective colloid agent, thepolymerization stability can be further enhanced.

The chain transfer agent includes, for example, a mercaptan, forexample, n-dodecyl mercaptan, octyl mercaptan, tert-butyl mercaptan,thioglycolic acid, thiomalic acid, or thiosalicylic acid, a sulfide, forexample, diisopropyl xanthogen disulfide, diethyl xanthogen disulfide ordiethyl thiuram disulfide, a halogenated hydrocarbon, for example,iodoform, diphenyl ethylene, p-chlorodiphenyl ethylene, p-cyanodiphenylethylene, and α-methyl styrene dimer. By performing the emulsionpolymerization in the presence of the chain transfer agent, themolecular weight can be controlled.

The polymerization initiator includes, for example, a persulfate, forexample, ammonium persulfate or potassium persulfate, a peroxide, forexample, hydrogen peroxide or benzoyl peroxide, and a redoxpolymerization initiator in which a persulfate and a reducing agent, forexample, an alkali metal sulfite or bisulfite are combined. The additionmethod of the polymerization initiator is not particularly limited andincludes, for example, a method of adding the total amount thereof atonce, a method of adding it dividedly in plural times and a method ofadding it dropwise.

The crosslinking agent includes, for example, a complete alkyl typemethylated melamine resin, for example, hexamethoxymethylated melamineresin, a partially alkylated methylated melamine resin, an amino resin,for example, a benzoguanamine resin or an alkyl-etherified urea resin,an isocyanate compound, for example, tolylene diisocyanate,diphenylmethane diisocyanate, triphenylmethane triisocyanate, xylylenediisocyanate, hydrogenated products thereof, hexamethylene diisocyanate,isophorone diisocyanate, dianisidine diisocyanate, or tolidinediisocyanate, a blocked isocyanate compound obtained by blocking theisocyanate group of the isocyanate compound described above, a phenolicresin, for example, a dimethylol resin, a poly methylol phenolic resin,a phenol formamide resin, a methylol phenol formamide resin, or adimethylol phenolic formamide resin, an epoxy resin, for example, apolyglycidyl ether of polyvalent alcohol, for example, ethylene glycoldiglycidyl ether, hexanediol diglycidyl ether, neopentyl glycoldiglycidyl ether, glycerol diglycidyl ether, glycerol polyglycidylether, diglycerol polyglycidyl ether, sorbitol polyglycidyl ether,hydrogenated bisphenol A diglycidyl ether, or bisphenol A diglycidylether, p-oxybenzoic acid glycidyl ether, phthalic acid diglycidyl ester,hexahydrophthalic acid diglycidyl ester, a hydantoin ring-containingepoxy resin, or a vinyl polymer having an epoxy group in the side chainthereof, an aziridine compound, for example,tris-2,4,6-(1-aziridinyl)-1,3,5-triazine,tris[1-(2-methyl)aziridinyl]phosphine oxide orhexa[1-(2-methyl)aziridinyl]triphosphatriazine, an oxazolinering-containing compound, an alkyd resin, an unsaturated polyesterresin, and a polyvalent alcohol.

In the emulsion polymerization described above, an additional componentmay further be used. Such a component includes, for example, a wettingagent, an antifoaming agent, a foaming agent, a foam stabilizer, athickener, a penetrating agent, a water repellent oil repellent agent, aplasticizer, a preservative, an antifungal agent, a germicide, a rustinhibitor, a chelating agent, an antioxidant, an ultraviolet absorber, apH adjusting agent, a freeze-thaw stabilizer, a high boiling pointsolvent, a colorant, for example, an inorganic pigment or an organicpigment, a filler, metal powder, a humectant, an adhesion impartingagent, a vulcanizing agent, for example, zinc oxide, sulfur or avulcanization accelerator, an anti-blocking agent and a flame retardant.

A base material to which the aqueous resin dispersion of the presentinvention can be applied is not particularly limited and includes, forexample, a plastic, for example, polyethylene, polypropylene,polystyrene, an ABS resin, an acrylic resin, polycarbonate, polyvinylchloride, or polyethylene terephthalate, and in addition, rubber, wood,ceramic, glass, and metal.

The coating material according to the present invention is one whichcontains the aqueous resin dispersion described above.

EXAMPLE

The present invention will be described more specifically with referenceto the Examples, but the present invention should not be construed asbeing limited to these Examples. The “%” therein indicates “% by mass”unless otherwise specified. Further, in the structural formulae, EOrepresents oxyethylene, and PO represents oxypropylene.

Surfactants (A-1) to (A-5) each represented by the general formula (I)were synthesized by the methods of Synthesis Examples 1 to 5 describedbelow, respectively.

Synthesis Example 1

In a reaction vessel equipped with a stirrer, a thermometer and a refluxtube were charged 208 g (1.0 mol) of styrenated phenol (a mixture ofmonostyrenated phenol:distyrenated phenol:tristyrenated phenol=87:12:1(mass ratio)), 40 g (1.0 mol) of sodium hydroxide and 210 g of acetone,and the internal temperature was raised to 40° C. with stirring. Then,84 g (1.1 mol) of allyl chloride was added dropwise thereto over aperiod of one hour, and after the completion of the dropwise addition,the mixture was allowed to react at 40° C. for 2 hours. The reactionproduct was filtered to remove NaCl by-produced, allyl styrenated phenylether was then obtained by removing acetone under a reduced pressure,and 280 g of 2-allyl styrenated phenol was obtained by further allowingto react at 200° C. for 5 hours.

To an autoclave was transferred 280 g of the 2-allyl styrenated phenolobtained, followed by addition reaction with 220 g (5 mol) of ethyleneoxide using potassium hydroxide as a catalyst under conditions ofpressure of 0.15 MPa and temperature of 130° C., thereby obtainingpolyoxyethylene propenyl styrenated phenyl ether. Subsequently, thepolyoxyethylene propenyl styrenated phenyl ether obtained wastransferred to a reaction vessel equipped with a stirrer, a thermometerand a nitrogen inlet tube, and subjected to a reaction with 97 g (1 mol)of sulfamic acid in nitrogen atmosphere under condition of temperatureof 120° C. Then, monoethanolamine was added to adjust pH of a 1% byweight aqueous solution to 7.5, followed by filtration to remove thesalt formed, thereby obtaining Surfactant (A-1) represented by formula(1) shown below.

Synthesis Example 2

The same procedure as in Synthesis Example 1 was performed except forusing 220 g (1.0 mol) of a mixture of monostyrenated phenol:distyrenatedphenol:tristyrenated phenol=80:19:1 (mass ratio) as the styrenatedphenol and changing the use amount of allyl chloride to 91 g (1.2 mol)and the use amount of ethylene oxide to 440 g (10 mol), therebyobtaining Surfactant (A-2) represented by formula (2) shown below.

Synthesis Example 3

The same procedure as in Synthesis Example 1 was performed except forusing 253 g (1.0 mol) of a mixture of monostyrenated phenol:distyrenatedphenol:tristyrenated phenol=60:30:10 (mass ratio) as the styrenatedphenol and changing the use amount of allyl chloride to 114 g (1.5 mol)and the use amount of ethylene oxide to 2,200 g (50 mol), therebyobtaining Surfactant (A-3) represented by formula (3) shown below.

Synthesis Example 4

To an autoclave was transferred 310 g of the 2-allyl styrenated phenolobtained by the same procedure as in Synthetic Example 2, followed byaddition reaction with 58 g (1 mol) of propylene oxide and then additionreaction with 440 g (10 mol) of ethylene oxide using potassium hydroxideas a catalyst under conditions of pressure of 0.15 MPa and temperatureof 130° C., thereby obtaining polyoxyalkylene propenyl styrenated phenylether.

Subsequently, the polyoxyalkylene propenyl styrenated phenyl etherobtained was transferred to a reaction vessel equipped with a stirrer, athermometer and a nitrogen inlet tube, and subjected to a reaction with97 g (1 mol) of sulfamic acid in nitrogen atmosphere under condition oftemperature of 120° C. Then, monoethanolamine was added to adjust pH ofa 1% by weight aqueous solution to 7.5, followed by filtration to removethe salt formed, thereby obtaining Surfactant (A-4) represented byformula (4) shown below.

Synthesis Example 5

The same procedure as in Synthesis Example 2 was performed except forusing 237 g (1.0 mol) of styrenated methylphenol (a mixture ofmonostyrenated methylphenol:distyrenated methylphenol:tristyrenatedmethylphenol=80:19:1 (mass ratio)) in place of the styrenated phenol,thereby obtaining Surfactant (A-5) represented by formula (5) shownbelow.

The compounds shown below were used as surfactants for comparativeexamples.

(a-1) Polyoxyethylene-1-(allyloxymethyl)alkyl ether sulfate esterammonium salt (trade name: AQUALON KH-10, produced by DKS Co. Ltd.)

(a-2) Polyoxyethylene-1-(allyloxymethyl)nonylpropenylphenyl ethersulfate ester ammonium salt (trade name: HITENOL A-10, produced by DKSCo. Ltd.)

As the surfactant (B) free from a radical-polymerizable substituent, thecompounds described below were used.

(B-1) Polyoxyethylene styrenated phenyl ether (trade name: NOIGENEA-177, produced by DKS Co. Ltd.)

(B-2) Polyoxyalkylene branched decyl ether (trade name: NOIGEN XL-400D,produced by DKS Co. Ltd.)

(B-3) Polyoxyethylene tridecyl ether (trade name: NOIGEN TDS-200D,produced by DKS Co. Ltd.)

(B-4) Polyoxyethylene lauryl ether (trade name: DKS NL-180, produced byDKS Co. Ltd.)

(B-5) Polyoxyethylene oleyl cetyl ether (trade name: NOIGEN ET-18E,produced by DKS Co. Ltd.)

(B-6) Polyoxyalkylene branched decyl ether (trade name: EPAN 750,produced by DKS Co. Ltd.)

(B-7) Polyoxyethylene styrenated phenyl ether sulfate ester ammoniumsalt (trade name: HITENOL NF-13, produced by DKS Co. Ltd.)

(B-8) Polyoxyalkylene branched decyl ether sulfate ester ammonium salt(trade name: HITENOL XJ-160, produced by DKS Co. Ltd.)

(B-9) Polyoxyethylene lauryl ether sulfate ester ammonium salt (tradename: HITENOL LA-16, produced by DKS Co. Ltd.)

(B-10) Polyoxyethylene oleyl cetyl ether sulfate ester ammonium salt(trade name: HITENOL 18E, produced by DKS Co. Ltd.)

(B-11) Sodium straight-chain alkylbenzenesulfonate (trade name: NEOGENS-20F, produced by DKS Co. Ltd.)

(B-12) Sodium dioctyl sulfosuccinate (trade name: NEOCOL P, produced byDKS Co. Ltd.)

(B-13) Polyoxyethylene styrenated phenyl ether phosphoric acid ester(trade name: PLYSURF AL, produced by DKS Co. Ltd.)

Examples 1 to 17 and Comparative Examples 1 to 9

The surfactant (A) and surfactant (B) having the kinds and amounts (g)shown in Table 1 or Table 2 were dissolved in 107.15 g of water. To thiswere added 123.75 g of butyl acrylate, 123.75 g of styrene and 2.5 g ofacrylic acid, followed by emulsifying by a homomixer, thereby obtaininga pre-emulsion.

Separately, 117.11 g of water and 0.25 g of sodium hydrogen carbonatewere charged to a flask equipped with a dropping funnel, a stirrer, anitrogen gas inlet tube, a thermometer, and a reflux condenser, and36.46 g of the pre-emulsion described above was added thereto, followedby temperature increase to 80° C. and mixing for 15 minutes. An aqueoussolution prepared by dissolving 0.38 g of ammonium persulfate in 10 g ofwater as a polymerization initiator was added thereto to initiatereaction. From 15 minutes after the addition of the polymerizationinitiator, the remaining pre-emulsion was added dropwise over a periodof 3 hours and allowed to react further for one hour. Subsequently, anaqueous solution prepared by dissolving 0.12 g of ammonium persulfate in10 g of water was added and allowed to react for one hour, followed bycooling to 40° C. and adjusting pH to 8 with aqueous ammonia, therebyobtaining an aqueous resin dispersion.

TABLE 1 Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5 Ex. 6 Ex. 7 Surfactant A-1 4.0 (A)A-2 4.0 4.0 4.0 A-3 A-4 4.0 A-5 4.0 4.0 Surfactant B-1 1.0 (B) B-2 1.0B-3 1.0 B-4 1.0 B-5 1.0 B-6 1.0 B-7 1.0 B-8 B-9 B-10 B-11 B-12 B-13Evaluation Copolymerizability ◯ ◯ ◯ ◯ ◯ ◯ ◯ of of Surfactant (A) AqueousPolymerization Stability <0.01 0.02 0.01 0.01 0.02 <0.01 0.01 Resin (%by weight) Dispersion Average Particle 156 158 155 158 153 157 145Diameter (nm) Polydispersity 0.12 0.26 0.23 0.27 0.25 0.29 0.16 ChemicalStability ◯◯ ◯◯ ◯◯ ◯◯ ◯◯ ◯◯ ◯ Mechanical Stability <0.01 0.01 0.02 0.020.03 0.01 <0.01 (% by weight) Low Foaming ◯◯ ◯◯ ◯◯ ◯◯ ◯◯ ◯◯ ◯◯ PropertyWettability to Base ◯ ◯ ◯ ◯ ◯ ◯ ◯ Material Evaluation Pencil Hardness HBHB HB HB HB HB HB of Test Glossiness ◯ ◯ ◯ ◯ ◯ ◯ ◯ Piece Water Whitening◯ ◯ ◯ ◯ ◯ ◯ ◯ Having Resistance Coating Water Absorption ◯ ◯ ◯ ◯ ◯ ◯ ◯Film Rate Elution Rate ◯ ◯ ◯ ◯ ◯ ◯ ◯ Ex. 8 Ex. 9 Ex. 10 Ex. 11 Ex. 12Ex. 13 Surfactant A-1 4.0 (A) A-2 4.0 A-3 4.0 A-4 4.0 4.0 A-5 4.0Surfactant B-1 (B) B-2 B-3 B-4 B-5 B-6 B-7 B-8 1.0 B-9 1.0 B-10 1.0 B-111.0 B-12 1.0 B-13 1.0 Evaluation Copolymerizability ◯ ◯ ◯ ◯ ◯ ◯ of ofSurfactant (A) Aqueous Polymerization Stability 0.02 <0.01 0.01 0.010.02 0.01 Resin (% by weight) Dispersion Average Particle 146 141 144140 140 149 Diameter (nm) Polydispersity 0.15 0.14 0.13 0.15 0.12 0.28Chemical Stability ◯ ◯ ◯ ◯ ◯ ◯ Mechanical Stability 0.01 0.02 0.02 0.030.01 0.02 (% by weight) Low Foaming ◯◯ ◯◯ ◯◯ ◯◯ ◯◯ ◯◯ PropertyWettability to Base ◯ ◯ ◯ ◯ ◯ ◯ Material Evaluation Pencil Hardness HBHB HB HB HB HB of Test Glossiness ◯ ◯ ◯ ◯ ◯ ◯ Piece Water Whitening ◯ ◯◯ ◯ ◯ ◯ Having Resistance Coating Water Absorption ◯ ◯ ◯ ◯ ◯ ◯ Film RateElution Rate ◯ ◯ ◯ ◯ ◯ ◯

TABLE 2 Com. Com. Com. Ex. 14 Ex. 15 Ex. 16 Ex. 17 Ex. 1 Ex. 2 Ex. 3Surfactant A-2 4.5 3.5 2.0 12.0 5.0 (A) Surfactant B-1 0.5 1.5 0.5 3.05.0 (B) B-2 B-3 5.0 B-4 B-7 B-9 Other a-1 Surfactant a-2 EvaluationCopolymerizability ◯ ◯ ◯ ◯ ◯ — — of of Surfactant (A) AqueousPolymerization 0.01 0.02 0.03 <0.01 0.01 0.12 0.14 Resin StabilityDispersion (% by weight) Average Particle 140 160 178 134 145 187 185Diameter (nm) Polydispersity 0.11 0.27 0.30 0.11 0.27 0.36 0.37 ChemicalStability ◯◯ ◯◯ ◯◯ ◯◯ ◯ ◯◯ ◯◯ Mechanical 0.01 0.01 0.02 0.01 0.01 0.350.45 Stability (% by weight) Low Foaming ◯◯ ◯◯ ◯◯ ◯◯ ◯◯ X X PropertyWettability to Base ◯ ◯ ◯ ◯ X ◯ ◯ Material Evaluation Pencil Hardness HBHB HB HB HB B B of Test Glossiness ◯ ◯ ◯ ◯ ◯ X X Piece Water Whitening ◯◯ ◯ ◯ ◯ X X Having Resistance Coating Water Absorption ◯ ◯ ◯ ◯ ◯ X XFilm Rate Elution Rate ◯ ◯ ◯ ◯ ◯ X X Com. Com. Com. Com. Com. Com. Ex. 4Ex. 5 Ex. 6 Ex. 7 Ex. 8 Ex. 9 Surfactant A-2 (A) Surfactant B-1 1.0 (B)B-2 1.0 B-3 B-4 1.0 B-7 5.0 B-9 4.0 Other a-1 5.0 4.0 Surfactant a-2 5.04.0 Evaluation Copolymerizability — — X X X X of of Surfactant (A)Aqueous Polymerization 0.01 0.01 0.01 0.02 0.01 0.01 Resin StabilityDispersion (% by weight) Average Particle 148 150 147 148 155 153Diameter (nm) Polydispersity 0.28 0.30 0.27 0.26 0.25 0.26 ChemicalStability ◯ ◯◯ ◯ ◯ ◯◯ ◯◯ Mechanical Stability 0.30 0.40 0.01 0.02 0.020.01 (% by weight) Low Foaming X X ◯◯ ◯◯ X X Property Wettability toBase ◯ ◯ X X ◯ ◯ Material Evaluation Pencil Hardness B B HB HB HB HB ofTest Glossiness X X ◯ ◯ ◯ ◯ Piece Water Whitening X X ◯ ◯ X X HavingResistance Coating Water Absorption X X ◯ ◯ X X Film Rate Elution Rate XX ◯ ◯ X X

As to the aqueous resin dispersions obtained, copolymerizability of thesurfactant (A), polymerization stability, average particle diameter,polydispersity, chemical stability, mechanical stability, foamingproperty (low foaming property), and wettability to base material wereevaluated. The results are shown in Table 1 and Table 2.

[Copolymerizability of Surfactant (A)]

The aqueous resin dispersion was diluted 5 times with methanol. Theresulting diluted solution was subjected to ultracentrifugationtreatment (trade name: himac CS 120FX, produced by Hitachi Koki Co.,Ltd.) to separate a resin and a supernatant liquid and the supernatantliquid was collected. The supernatant liquid obtained was measured by ahigh performance liquid chromatography equipped with an UV detector tocalculate a weight of the surfactant (A) which had not been polymerizedby using a calibration curve method, and a polymerization rate of thesurfactant (A) was calculated according to the equation shown below. Asthe polymerization rate of the surfactant (A) increases, the property isgood, and the evaluation was conducted according to the criteria shownbelow.

$\begin{matrix}{{{Polymerization}\mspace{14mu} {rate}\mspace{14mu} (\%)\mspace{14mu} {of}\mspace{14mu} {surfactant}\mspace{14mu} (A)} = {\frac{\begin{matrix}{\left( {{Weight}\mspace{14mu} {of}\mspace{14mu} {surfactant}\mspace{14mu} (A)\mspace{14mu} {used}} \right) -} \\\left( {{Weight}\mspace{14mu} {of}\mspace{14mu} {surfactant}\mspace{14mu} (A)\mspace{14mu} {not}\mspace{14mu} {polymerized}} \right)\end{matrix}}{\left( {{Weight}\mspace{14mu} {of}\mspace{14mu} {surfactant}\mspace{14mu} (A)\mspace{14mu} {used}} \right)} \times 100}} & \left\lbrack {{Math}.\mspace{14mu} 1} \right\rbrack\end{matrix}$

◯: The polymerization rate of the surfactant (A) is 80% or more.x: The polymerization rate of the surfactant (A) is 40% or more but lessthan 80%.x x: The polymerization rate of the surfactant (A) is less than 40%.

[Polymerization Stability]

100 g of the aqueous resin dispersion was filtered through a 200-meshmetal gauze and then the residue was washed with water and the residuewas dried at 105° C. for 2 hours. Subsequently, the weight of the driedproduct was measured and the aggregate concentration (% by weight) inthe aqueous resin dispersion was calculated. Separately, 1 g of theaqueous resin dispersion was dried at 105° C. for 2 hours, the weight ofthe dried product was measured and the solid content concentration (% byweight) in the aqueous resin dispersion was calculated. By using theaggregate concentration and solid content concentration thus-calculated,a ratio of the aggregate was calculated according to the equation shownbelow. As the ratio of aggregate decreases, the polymerization stabilityis high.

(Ratio of aggregate (% by weight))=[(Aggregate concentration)/(Solidcontent concentration)]×100

[Average Particle Diameter]

The average particle diameter (nm) of the aqueous resin dispersion wasmeasured by using a dynamic light scattering particle size distributionanalyzer (produced by Nikkiso Co., Ltd., product name: MICROTRACUPA9340). The average particle diameter is a median diameter of d50.

[Polydispersity]

The three kinds of the average particle diameter (nm) of the aqueousresin dispersion were measured by using a dynamic light scatteringparticle size distribution analyzer (produced by Nikkiso Co., Ltd.,product name: MICROTRAC UPA9340) and the polydispersity was calculatedaccording to the calculation equation shown below.

Polydispersity=(d90−d10)/d50

d90: Particle diameter corresponding to 90% of the volume distributioncumulative amount in the particle diameter distribution curve

d10: Particle diameter corresponding to 10% of the volume distributioncumulative amount in the particle diameter distribution curve

d50: Particle diameter (median diameter) corresponding to 50% of thevolume distribution cumulative amount in the particle diameterdistribution curve

[Chemical Stability]

To 10 g of the aqueous resin dispersion was added 10 ml of an aqueouscalcium chloride solution having a predetermined concentration, followedby stirring for 5 minutes. Then the occurrence or non-occurrence ofaggregate was confirmed by visual observation. The concentration of theaqueous calcium chloride solution was set to 0.5 mol/L, 1.0 mol/L or 2.0mol/L and the lowest concentration at which the aggregate occurred wasdetermined. As the numerical value increases, the chemical stability ishigh and the evaluation was conducted according to the criteria shownbelow.

◯◯: 2.0 mol/L or non-occurrence of aggregate◯: 1.0 mol/Lx: 0.5 mol/L

[Mechanical Stability]

50 g of the aqueous resin dispersion was treated in a Marlon type testerunder a load of 10 kg at a rotation number of 1,000 rpm for 5 minutes.The resulting treated solution was filtered through a 100-mesh metalgauze, and the residue was washed with water and then dried at 105° C.for 2 hours to collect the aggregate. The weight of the aggregate wasmeasured and the ratio of aggregate (% by weight) was calculated in thesame manner as in the polymerization stability. As the numerical valuedecreases, the mechanical stability is high.

[Low Foaming Property]

20 ml of the aqueous resin dispersion and 10 ml of water were put into a100-ml Nessler tube, followed by inverting 50 times and then allowing tostand. An amount of foam (mL) after 5 minutes was measured. As theamount of foam decreases, the property is good and the evaluation wasconducted according to the criteria shown below.

◯◯: Amount of foam is less than 6 mL.◯: Amount of foam is 6 ml or more but less than 10 mL.x: Amount of foam is 10 ml or more.

[Wettability to Base Material]

By using one obtained by diluting the aqueous resin dispersion twicewith water, surface tension (mN/m) at 25° C. was measured by a Wilhelmytype surface tension meter. As the surface tension decreases, thewettability to a base material is high and the evaluation was conductedaccording to the criteria shown below.

◯: Surface tension is less than 40 mN/m.x: Surface tension is 40 mN/m or more.

The aqueous resin dispersion obtained was applied on a glass plate so asto have a dry coating thickness of 120 μm, and dried in an atmosphere of20° C.×65% RH for 24 hours, thereby preparing a test piece having acoating film. Using the test piece, pencil hardness, glossiness, waterwhitening resistance, water absorption rate, and elution rate wereevaluated. The results are shown in Table 1 and Table 2.

[Pencil Hardness]

The pencil hardness was measured based on the method of JIS K5600-5-4(1999).

[Glossiness]

The gloss of 60 degree specular reflection was measured by aphotoelectric gloss meter (trade name: TC-108DP/A, produced by TokyoDenshoku Co., Ltd.). As the angle increases, the property is good, andthe glossiness was evaluated according to the criteria shown below.

◯◯: 80 degree or more◯: 70 degree or more but less than 80 degreeΔ: 50 degree or more but less than 70 degreex: Less than 50 degree

[Water Whitening Resistance]

The test piece was immersed in ion-exchanged water at 70° C. and thenwater on the surface of test piece was removed. This was put on paperprinted with 10-point characters and the time of immersion until thecharacters became invisible was measured. As the time of immersionincreases, the property is good, and the evaluation was conductedaccording to the criteria shown below.

◯: Characters are visible even after immersion for 3 days.x: Characters become invisible within 3 days.

[Water Absorption Rate]

The coating film was peeled from the glass plate, cut into a size of 5cm×5 cm, and the weight thereof (weight a) was measured. Subsequently,this was immersed in ion-exchanged water at 70° C. for 72 hours, andafter softly wiping off water on the surface thereof with a filterpaper, the weight (weight b) of the coating film was measured. By usingthe weight a and the weight b each measured, the water absorption ratewas calculated according to the calculation equation shown below. As thewater absorption rate decreases, the property is good, and theevaluation was conducted according to the criteria shown below.

Water absorption rate (% by weight)=[(Weight b−Weight a)/Weight a]×100

◯: The water absorption rate is less than 20% by weight.x: The water absorption rate is 20% by weight or more.

[Elution Rate]

The coating film was peeled from the glass plate, cut into a size of 5cm×5 cm, and the weight thereof (weight a) was measured. Subsequently,this was immersed in ion-exchanged water at 20° C. for 72 hours, andthen the coating film was taken out from the water, and dried at 105° C.for 3 hours. The weight (weight c) of the coating film after drying wasmeasured, and the elution rate of the coating film was calculatedaccording to the calculation equation shown below. As the elution ratedecreases, the property is good, and the evaluation was conductedaccording to the criteria shown below.

Elution rate (% by weight)=[(Weight c−Weight a)/Weight a]×100

◯: The elution rate is less than 2% by weight.x: The elution rate is 2% by weight or more.

From the results described above, it can be seen that since the aqueousresin dispersion of the present invention is one obtained by subjectingthe polymerizable compound (C) to emulsion polymerization in thepresence of the surfactant (A) and the surfactant (B), not only theoccurrence of foam, the decrease in water resistance of coating film andthe elution of surfactant from the coating film are suppressed, but alsothe wettability to base material is excellent. On the other hand, in thecase of using only the surfactant (A) as in Comparative Example 1, itcan be seen that the wettability to base material is poor. In the caseof using only the surfactant (B) as in Comparative Examples 2 to 5, itcan be seen that the stability, the low foaming property and thephysical properties of the coating film are poor. Further, in the caseof using other surfactant having a radical-polymerizable substituent inplace of the surfactant (A) as in Comparative Examples 6 and 7, it canbe seen that the copolymerizability of surfactant and the wettability tobase material are poor. In the case of using the other surfactantdescribed above and the surfactant (B) as in Comparative Examples 8 and9, it can be seen that the low foaming property and the physicalproperties of the coating film are poor.

INDUSTRIAL APPLICABILITY

Since the aqueous resin dispersion of the present invention is excellentin the wettability and adhesion to various base materials and is alsoexcellent in the water resistance, it can be used as a coating materialor an adhesive for buildings, bridges, interior and exterior materialsof housing, furniture, automobiles, interior and exterior materials oftransport vehicles, and the like.

While the present invention has been described in detail and withreference to specific embodiments thereof, it will be apparent to oneskilled in the art that various changes and modifications can be madetherein without departing from the spirit and scope of the presentinvention.

The present application is based on a Japanese patent application No.2014-229348 filed on Nov. 11, 2014, the content thereof beingincorporated herein by reference.

1. An aqueous resin dispersion, obtained by subjecting a polymerizablecompound (C) comprising a compound (C1) having a carbon-carbonunsaturated bond to an emulsion polymerization in the presence of asurfactant (A) represented by a general formula (I) shown below and asurfactant (B) free from a radical-polymerizable substituent:

wherein in the general formula (I), R⁰ represents an alkyl group havinga carbon number of from 1 to 4, le represents at least one groupselected from substituents represented by structural formulae describedabove, in these structural formulae, R² represents a hydrogen atom or amethyl group, D represents a substituent represented by general formulaD-1 or D-2 shown above, in these structural formulae, R³ represents ahydrogen atom or a methyl group, m1 represents a number of from 1 to 2,m2 represents a number of from 1 to 3, m3 represents a number of 0 or 1,AO represents an oxyalkylene group having a carbon number of from 2 to4, n is an average addition molar number of alkylene oxide andrepresents a number in a range of from 0 to 1,000, and X represents agroup selected from —(CH₂)_(a)—SO₃M, —(CH₂)_(b)—COOM, —PO₃M₂, —P(Z)O₂M,and —CO—CH₂—CH(SO₃M)-COOM, in these structural formulae, a and b eachrepresents a number of from 0 to 4, Z represents a residue in which X iseliminated from the general formula (I), and M each represents ahydrogen atom, an alkali metal atom, an alkaline earth metal atom, analkyl ammonium, an alkanol ammonium, or an ammonium.
 2. The aqueousresin dispersion according to claim 1, wherein a ratio of the surfactant(B) is from 5 to 80 parts by mass based on 100 parts by mass of thesurfactant (A).
 3. The aqueous resin dispersion according to claim 1,wherein the surfactant (B) is a nonionic surfactant (B 1).
 4. Theaqueous resin dispersion according to claim 1, which is for use in acoating material.
 5. A coating material, comprising the aqueous resindispersion according to claim
 1. 6. The aqueous resin dispersionaccording to claim 2, wherein the surfactant (B) is a nonionicsurfactant (B 1).
 7. The aqueous resin dispersion according to claim 2,which is for use in a coating material.
 8. The aqueous resin dispersionaccording to claim 3, which is for use in a coating material.
 9. Acoating material, comprising the aqueous resin dispersion according toclaim
 2. 10. A coating material, comprising the aqueous resin dispersionaccording to claim 3.